Screen.



No. 645,072. Patented Mar. I3,l900.

G. W. GROSS.

SCREEN.

(Application filed. Aug. 4, 1898.)

(No Model.)

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SCREEN.

SPECIFICATION forming part of Letters Patent No. 645,072, dated March13, 1900. Application filed August 4, 1898. Serial No. 687,680. 7 (Nomodel.)

To all whom it may concern;

Be it known that I, GEORGE W. GROSS, a citizen of the United States,residing at Oarbondale, in the county of Lackawanna and State ofPennsylvania, have invented a certain new and useful Improvement inScreens, of which the following is a specification.

This invention relates to the perforated surfaces of screens designedfor the separation of coal and other material into predetermined sizes.Particularly the invention concerns that type of screening-surface knownin the art as crimped, and consisting generally of a continuous jacketor integral segments, the interstices, preferably quadrilateral in form,

being surrounded by webs, to which, or to certain of which,variouscurvatures are given, raising them above or depressing them belou theworking surface of the screen. In the construction of segments orjackets of this type two import-ant considerations are present. Thefirst of these is that the surface should attain maximum efficiency inthe separating operation-that is to say, the coal or other material inits passage through the screen must be subjected to such action by thescreeningsurface as to facilitate the passage of the material throughthe perforations, provided the particles are of the size intended topass therethrough. The other consideration referred to is that thesurface as a whole must present maximum strength to withstand the actionof the coal or other material passing through the screen. In manyscreens heretofore devised the second consideration has been sacrificedto the first. In other words, in attempting to attain the maximum degreeof efficiency in the separating operation the screening-surface as awhole has been weakened to such an extent as to give way after certainof the webs bounding the interstices have been worn, both by the actionof the material passing through the screen and by corrosion, 850.

The object of the present invention is to satisfactorily meet bothrequirements above stated, and, moreover, to do this by the provision ofa screening-surface which may be readily and therefore cheaply crimpedor otherwise fashioned by any convenient means-- such, for instance, asby dies or rollers.

The invention is illustrated in the accoin panying drawings, in which--Figure 1 is a plan view of a screen-segment embodying my improvement.Fig. 2 is a transverse section on the line 2 2 of Fig. 1. Fig. 3 is atransverse section on the line 3 3 of Fig. 1, and Fig. 4 is alongitudinal section on the line 4: 4 of Fig. 1.

Referring to the drawings, in which. similar letters of reference denotecorresponding parts, it will be seen that the invention is disclosed asembodied in a segment rather than in a continuous jacket, such as abovereferred to, and that this segment consists of a sheet of steel or othersuitable material, the perfo rations therein being so arranged as toleave side margins at a. and end margins a or. This construction, whilenot imperative, is desirable on account of the added strength of thesegment. The margins may be provided with the usual bolt-holes toprovide for the attachment of the segment to a revoluble screen. One ormore of the edges or margins of the plate may also be provided withtumblers or other appliances of any desired de scription. Such tumblersor other appliances forming no part of the present invention are notillustrated herein.

Referring now to the interstices h in the segment, these, as will beseen, are substantially quadrilateral. in form, the corners beingslightly rounding, rather than angular, to prevent weakening the webs.Each of the interstices b is bounded by two transverse webs c and c andby two longitudinal webs cl and d.

After the plate has been provided with the perforations describedcertain of the webs thereof are crimped or curved in the followingmanner: The alternate webs, both trans verse and longitudinal, are madesinuous in form in such manner as that at one junction e the transversewebs shall be elevated, while at the next adjacent junction f the web isdepressed or left in the original plane of the sheet. The same is trueof the undulating longitudinal webs, one junction 9 of each of such websbeing elevated, while at the next adjacent junction h the web isdepressed or left in the plane of the sheet. This operation, repeatedover the entire surface of the segtnent, leaves a nur'nber of junctionsbetween transverse and longitudinal Webs which are elevated above theoriginal plane of the plate, each of which junctions, together with the'webs extending outwardly therefrom in the longitude and the latitude ofthe segment, separates four adjacent and substantially quadrilateralinsterstices, while all of the eight junctions with which thoselongitudinally and transversely extending webs are connected remain inthe original plane of the plate.

Due to the construction above described the coal or other material inits passage through the revolving screen will be prevented from slidingover the surface of the segment or jacket, but will, on the contrary, becontinuously turned over or tumbled or otherwise agitated by theprojecting webs and junctions which extend inwardly toward the axis ofthe screen. More than this, such particles of material as are of theproper size to pass through the perforations are guided to theperforations and their passage therethrough assured. In attaining thisresult I am able by means of the construction described to dispenseentirely with sharp curvatures of the webs bounding the interstices,which curvatures have a tendency to weaken the screening-surface. Thusinstead of crimping or curving inwardly or outwardly one web boundingone side of that interstice the only curvature of the Webs of thepresent construction is that of two contiguous webs, together with theintermediate junction. The curvatures, therefore, in the screen-surfaceherein shown and described are of relatively greater size than thoseheretofore employed, and therefore necessarily more gradual. Added tothis is the fact that where, for instance, a longitudinal web is curvedinwardly toward the axis of the screen it is met mid way by acorrespondingly-curved transverse web and the whole are united by anelevated junction, which receives the weight of the coal and addsgreatly to the strength and rigidity of the segment.

Although I have described my present invention as applied to ascreen-segment, it is obvious that the same might equally well beutilized in continuous jackets for revoluble screens such as haveheretofore been employed in this art.

Having now described my invention, what I claim, and desire to secure byLetters Pat ent, is

1. An integral screen-surfaceprovided'with substantially-quadrilateralinterstices, four of said interstices being bounded by webs lying insubstantially the same plane but separated from each other by websextending above that plane, substantially as set fort-h.

2. An integral screen-surface having substantially-quadrilateralinterstices, each in-- terstice being bounded by four webs,'two,adjoining and connecting, webs of said four being arranged above theplane of the other two,

